Safety device in a motor vehicle

ABSTRACT

A safety device in a motor vehicle comprises a roller retractor ( 2 ) mounted at the top of the back ( 1 ) of a vehicle seat. The roller retractor ( 2 ) has wound on it a sheet-like element or net ( 3 ) which is extractable from the roller to engage anchoring means secured in or adjacent the roof of the vehicle. The length of net ( 3 ) to be extracted from the roller retractor ( 2 ) is different in different positions of the back of the seat. The roller retractor mechanism is associated with a locking mechanism ( 5 ) which is actuated in at least one of the alternative positions of the back of the seat to lock the extraction of more than a predetermined length of the sheet-like element from the roller retractor ( 2 ). The length is sufficient to enable the sheet to be secured to connecting means provided in the roof of the vehicle.

FIELD OF THE INVENTION

The present invention relates to a safety device in a motor vehicle andmore particularly relates to a safety device comprising a retainingelement connected to the back-rest of the rear seat of a motor vehicle,the retaining element being adapted to extend between the back-rest ofthe rear seat of the vehicle and the roof of the vehicle in order toprevent luggage stored in the vehicle behind the back-rest of the rearseat moving forwardly should an accident arise in which the vehiclestops suddenly.

BACKGROUND OF THE INVENTION

It has been proposed to provide previously a retaining element in theform of a retractable net provided on a retractor roller mountedadjacent the top of the rear back-rest of a motor vehicle such as, forexample, an estate car. In use, the net is pulled out over its fulllength and the free end of the net is engaged with anchorage pointsprovided in the roof of the motor vehicle. It is to be appreciated thatin this position, the net will prevent any objects present in the rearluggage compartment of the vehicle from moving forwardly into the partof the vehicle where the occupants of the vehicle are located, even ifthe vehicle does decelerate rapidly, for example in a crash. However, ifthe back-rest is tilted to a forward position, the net will be too shortto reach the roof. If the net is made long enough to reach the roof whenthe back-rest is in a tilted forward position, then when the back-restis in the elevated position, should an item of luggage impinge againstthe net during an accident situation, the net will have a sufficientlength to permit the luggage to move forwardly into the compartmentwhere the occupants of the vehicle are located.

The present invention seeks to provide an improved safety device.

SUMMARY OF THE INVENTION

According to this invention there is provided a safety device in a motorvehicle, the safety device comprising a roller retractor mountedadjacent the top of the back of a vehicle seat, the roller retractorhaving wound on it a sheet-like protective element, the seat back beingmoveable between alternate positions, the sheet-like element beingextractable from the roller retractor to engage anchoring means securedin or adjacent the roof of the vehicle, the length of sheet-likematerial extracted from the roller retractor being different in the saiddifferent positions of the back of the seat, the roller retractormechanism being associated with a locking mechanism, the lockingmechanism being actuated in at least one of the said positions of theseat to lock the roller retractor to prevent the extraction of more thana predetermined length of said sheet from the retractor roller, thelength being sufficient to enable the sheet to be secured to theconnecting means provided in the roof of the vehicle.

Preferably said retractor comprises a retractor roller, the said sheetbeing wound on the roller.

Conveniently the roller is prevented from rotating by the lockingmechanism.

Advantageously the locking mechanism comprises means adapted to engagean element co-rotating with the roller to prevent rotation of theroller, and actuating means, to actuate the engaging means, theactuating means incorporating a gear mechanism, there being selectivelypositionable means, which are positioned in dependence upon the positionof the back-rest, adapted to engage part of said gear to prevent furtherrotation of the gear and to actuate the engagement mechanism.

In one embodiment the gear arrangement comprises a planetary gear.

Conveniently the planetary gear arrangement comprises a ring gear whichis fixed in position relative to the back-rest, a planet holder which isrotatably mounted in position and which carries planet gears, and a sungear engaged with the planet gears, the sun gear being connected to thesaid engagement means, a latch being provided which is movable toselected positions in dependence upon the position of the back-rest, thelatch being adapted to engage engagement means provided on the planetholder.

Preferably the engagement means comprises one or more steps provided inthe outer periphery of the planet holder.

In an alternative embodiment the gear comprises a ring-gear which ismovably mounted in position, and adapted to be driven rotationally by asun gear, and a sun gear engaging the ring-gear, the sun gear beingconnected to the engagement means.

Advantageously a latch is provided which is movable to selectedpositions in dependence upon the position of the back-rest, the latchbeing adapted to engage engagement means provided on the ring-gear.

Conveniently the engagement means comprises one or more steps providedin the outer periphery of the ring-gear.

Advantageously the engagement means comprise a clamping member having aperiphery defining at least one cam surface and a movable elementlocated between the cam surface and a clamping surface that surroundsthe clamping member, the clamping member rotating with the rollerextractor, the locking mechanism serving to retain said movable elementsubstantially in position.

Conveniently a striker component is provided mounted in position andadapted to strike a locking member to cause the locking member to movewhen the seat back is moved to at least one predetermined position, themovement of the locking member changing the position of the latch.

Preferably the latch is carried by a catch that engages the lockingmember.

In order that the invention may be more readily understood, and so thatfurther features thereof may be appreciated, the invention will now bedescribed, by way of example, with reference to the accompanyingdrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic side view illustrating a foldable back-rest fora rear seat of a motor vehicle, and an associated retractable luggableretaining element in the form of a net,

FIG. 2 is a diagrammatic side view illustrating the back-rest of FIG. 1in three alternate positions,

FIG. 3 is an exploded view of an assembly mounted on the back-rest whichincorporates the retractable net, and also an element that is fixed inposition on the body of the motor vehicle,

FIG. 4 is a diagrammatic perspective view illustrating the componentshown in FIG. 3 when in the assembled state, whilst also illustratingthe component mounted on the body of the motor vehicle,

FIG. 5 is a side elevational view of the apparatus shown in FIG. 4,

FIG. 6 is a diagrammatic view illustrating the said component mounted onthe body of the motor vehicle, and also illustrating a catch mechanismand a planet carrier for a planetary gear arrangement in a firstcondition,

FIG. 7 is a view corresponding to FIG. 6 illustrating the arrangement ina second condition,

FIG. 8 is a view corresponding to FIGS. 6 and 7 illustrating thearrangement in the third condition,

FIG. 9 is a diagrammatic view illustrating the catch, and alsoillustrating the planetary gear arrangement (with parts thereof cut awayfor the sake of clarity of illustration) in a first condition,

FIG. 10 is a view corresponding to FIG. 9 illustrating the arrangementin the second condition,

FIG. 11 is a view corresponding to FIGS. 9 and 10 illustrating thearrangement in a third condition,

FIG. 12 is an exploded view illustrating the catch, and the planetcarrier, together with an associated manually operable lever, and alsoassociated with one component of a clutch assembly,

FIG. 13 is an exploded view of the clutch assembly,

FIG. 14 is an elevational view of the clutch in a first condition,

FIG. 15 is a scrap view illustrating the position of a roller formingpart of the clutch assembly when the clutch assembly is in the conditionillustrated in FIG. 14,

FIG. 16 is a view corresponding to FIG. 14 illustrating the clutchassembly in an alternative condition,

FIG. 17 is a view corresponding to FIG. 15 illustrating the position ofthe roller when the clutch is in the alternative condition of FIG. 16,

FIG. 18 is a view, with parts thereof cut away illustrating the catch, aring-gear and part of a clutch assembly of a modified embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1 of the accompanying drawings a back 1 ofthe rear seat of a vehicle is illustrated. The back 1 is provided,adjacent its upper edge, with a roller mechanism 2 extending the entirewidth of the back of the seat, which has retractably mounted upon it aluggage retaining element 3 in the form of a net. It is to be understoodthat alternatively the luggage retaining element could be in the form ofa blind or an appropriate sheet of fabric.

The upper edge of the net 3 is provided with a rigid reinforcing element4 adapted to be connected to anchoring means in the form of hooks or thelike provided in the roof of the motor vehicle.

A locking mechanism 5 is provided which is associated with the rollermechanism 2, and which will be described in greater details hereinafter.The locking mechanism 5 is provided to lock the retractor roller, toprevent further net being permitted to be withdrawn. Thus, when the netis in the operative position as illustrated in FIG. 1, should thevehicle in which the arrangement is provided be involved in an accidentwhich involves substantial deceleration, which might cause luggagelocated behind the seat back 1 to move forwardly, the net 3 will preventthe luggage from moving forwardly. However, the locking arrangement issuch that if the seat back is moved to an alternative position, afurther length of net may be paid out, the retractor roller netmechanism then again being locked to retain the net in position.

Thus, as can be seen in FIG. 2, the seat back 1 may have an initialposition 6 when the seat back reclines rearwardly. The net 3 is shownextending upwardly above the seat back, with the reinforcing rod 4engaging a hook 7 which may be provided in the roof of the motorvehicle.

The seat back 1 may be tilted forwardly slightly, to a position as shownat 8 in FIG. 2. The net 3 may still be connected to the same hook 7, butthe length of net extending between the back of the seat and the hook 7is now less than the length of net extending between the back of theseat and the hook 7 when the back of the seat is in the position 6.Consequently, some net has been drawn on to the roller retractor toachieve the condition illustrated by the numeral 8 in FIG. 2. Themechanism will, however, again lock the roller retractor in thisposition to prevent further net being paid out.

The back of the seat 1 may be folded forwardly to be substantiallyhorizontal, as shown at 9 in FIG. 2. A substantial length of net 3 maybe withdrawn from the roller retractor 2, the net extendingsubstantially vertically to a second hook 10 provided in the roof of themotor vehicle. In this condition, the full extent of the net has beenpaid out from the roller retractor mechanism.

Referring now to FIG. 3 of the accompanying drawings, the catcharrangement 5 and the retractor roller 2 are illustrated in an explodedform.

A striker component 10 is provided adapted to be mounted securely to thebody of the motor vehicle. The striker component 10 comprises twoparallel spaced apart cylindrical striker elements 11,12 inter-connectedby a bridging element 13.

The striker component 10 is positioned so that, as the seat back 1 ismoved pivotally from the position 9 illustrated in FIG. 2, towards theposition 6 as illustrated in FIG. 2, the striker elements enter a guideslot 14 formed in an end plate 15 which is mounted on the side part ofthe back 1 of the vehicle seat. The upper edge of the guide slot islinear and the lower edge is curved, the edges diverging adjacent themouth of the slot. The end plate 15 comprises a planar plate region 16defining forwardly extending wings 17,18, the slot 14 being formed inone of the wings 17 and in the planar portion 16.

The planar portion 16 defines an aperture 19 which receives a pivotingsupport stud 20, and further pivot support apertures 21,22 which will bereferred to hereinafter. The planar portion 16 also defines two fixingapertures 23,24 adapted to receive fastening screws or the like tosecure the end plate 15 in position.

The pivoting support stud 20 pivotally supports a locking element 25,which defines a substantially centrally located aperture 26 which ismounted on the stud 20, and which has a convoluted exterior which willbe described hereinafter in greater detail. The locking element 25 isassociated with a biassing spring 126 which imparts a predeterminedrotational bias to the locking element 25.

A catch 27 is provided which forms a further part of the lockingmechanism, the catch 27 comprising an elongate element defining anaperture 28 which is mounted on a pivot stud 29, the pivot stud beingreceived in the aperture 21. The catch 27 defines a forwardly extendingnose 30, on one side of the aperture 28 and on the other side of theaperture 28 defines a depending lug 31 and an axially extendingprojection 32 of cylindrical form.

The projection 32 is received within an aperture 33 formed in anelongate manually operable release arm 34. The release arm 34 defines afurther aperture 35 which is received on the pivot stud 29. A spring 36is provided to bias the manual release arm in a predetermined rotationaldirection.

A latch 36 is provided which is also mounted on the pivot support stud29. The latch 36 comprises two diverging arms 37,38. An aperture 39extending though the latch 36 is concentric with a tubular projection 40which provides a bearing effect. The arm 38 carries an axially extendingcylindrical projection 41. A biassing spring 42 is provided associatedwith the latch adapted to bias the latch in an appropriate direction.

The pivot stud 29 is formed on the exterior a planetary gear housing 41.The planetary gear housing is of substantially circular form havingco-axially mounted on the end face directed towards the end plate 15, afirst substantially cylindrical projection 42 of a further diameter anda co-axially located second cylindrical projection 43 of a lesserdiameter. Formed in the end face of the projection 43 is an aperture 44adapted to receive a bearing element, as will be described hereinafter,which is received in the bearing aperture 22 formed in the end plate 15.

A slot 45 is formed in the side wall of the projection 42 of greaterdiameter in the vicinity of the a pivot stud 29. The slot is so locatedthat when the latch 36 has been mounted on the pivot stud 29, the arm 37of the latch may be inserted through the slot 45 as the latch rotatesabout the pivot axis defined by the pivot stud 29.

The planetary gear housing is fixed to the back-rest of the motorvehicle and contains, within the part of the housing of greatestdiameter (i.e. not within the projections 42 or 43), a ring gear 46which is fixed in position and which has inner toothing 47. The ringgear 46 forms the outer gear of a planetary gear system. The planetarygear system incorporates a substantially circular gear carrier 48 whichwill be described hereinafter in greater detail, which defines threeapertures 49,50,51 at equi-spaced regions on which are mounted threeplanet gears 52,53,54 and which also defines a central aperture 55. Theplanet carrier 48 is located in the first cylindrical projection 42 ofgreatest diameter provided on the planetary gear housing 41. The planetgears 52,53,54 are then located in a position where they are co-planarwith the ring-gear 46 and have their outer-most teeth in engagement withthe toothing 47 provided on the ring-gear 46. A central sun gear 56 isprovided which defines a central aperture 57, the sun gear being locatedto be in engagement with the inner peripheries of the planetary gears52,53,54.

The sun gear 56 is associated with a spider element 57 having sixprojecting arms which form part of a clutch as will be described ingreater detail hereinafter. Three of the arms of the spider element 57are adapted to engage clamping rollers 58,59,60 which are held inposition against a clamping element 61 which has convoluted exterior(which will be described in greater detail hereinafter), which definecam surfaces. The clamping element 61 is located within a clamping ring62 which is connected to the open end of the planetary gear housing 41.

The spider 57 and the associated components, including the rollers58,59,60, the clamping element 61 and the clamping ring 62 form a clutchthat effectively secures the roller retractor mechanism 2 to the lockingarrangement 5 in order to lock the roller to prevent the withdrawal offurther net from the roller retractor mechanism 2.

The roller retractor mechanism 2, as can be seen more clearly in FIG. 3,comprises a roller drum 63 upon which the net 3 is wound. The rollerdrum has, at the illustrated end, a bearing 64 having a hexagonal outerperiphery, and a substantially cylindrical inner bore 65. The bore 65 ismounted on a support rod 66, the support rod 66 also rotatablysupporting the sun gear 56, and the planet carrier 48 (by passingthrough the aperture 45), and also passing through the aperture 44 inthe planetary gear housing 41 being received in the aperture 22 formedin the planar portion 16 of the end plate 15. A helical spring 67 isprovided located between the rod 66 and the drum 63 in order to providea rotational bias to the drum tending to retract the net 3 on to thedrum.

FIG. 4 illustrates the components of the locking mechanism 5 when in theassembled state. It can be seen that the projection 43 provided on theplanetary gear housing 41 serves the function of spacing the main partof the planetary gear housing 41 from the end plate 15 by an appropriatedistance to permit the locking element 25, the catch 27 and theassociated manual release lever 34 and also the latch 37 between theplanetary gear housing 41 and the end plate 15. It can be seen that thefree end of the manual release arm 34 is accessible.

The striker component 10 is illustrated in position, and it can be seenthat the striker elements 11,12 are aligned with the guide slot 14. Asshown in FIG. 5, the striker elements 11,12 of the striker component 10are located in at a position spaced apart in a horizontal plane. It canbe seen more clearly that the upper edge of the guide slot 14 is linear,whereas the lower edge is slightly curved.

Referring now to FIG. 6, the locking element 25 is illustrated, togetherwith the catch 27, the latch 36 and the planet carrier 48.

The locking element 25 has a convoluted exterior. An initial curvedregion 70, which is located at a position which is substantiallytangential with reference to the axis defined by the aperture 26 isinitially positioned, so that the depending lug 31, provided on thecatch 27, is resting upon the curved surface 70. The curved surface 70terminates, at its left-hand end, as shown in FIG. 7, with a recess 71.The configuration of the recess 71 corresponds with the configuration ofthe depending lug 31.

Adjacent the recess 71 is a substantially “U”-shaped channel 72 having awidth equal to the diameter of the striker element 12 of the strikercomponent 10. In an initial condition illustrated in FIG. 6, the channel72 is inclined downwardly towards the right, but an extension of theupper-most edge of the channel is co-aligned with the striker elements11,12.

Moving further in a clockwise direction about the outer periphery of thelocking element 25, it can be seen that the outer periphery defines,adjacent the lower wall of the channel 72, an outwardly directedabutment face 73 which is located adjacent a linear portion 74 whichmerges into a further inwardly directed U-shaped channel 75 which has awidth equal to the width of the striker element 11.

The planetary gear carrier 48 is of substantially circular form, but theouter periphery defining two radially inwardly directed discontinuitiesor steps. The step 80 represents a step between the outer-most peripheryof the planetary gear carrier 48, and the planetary gear carrier 48 thenhas an outer periphery portion 82 which is spaced from the aperture 55by a distance less than the distance to the periphery of the planetarygear carrier located on the other side of the inwardly directed step 80.Similarly the step 81 extends to a further arcuate portion 83 of theexterior of the planetary gear carrier 48, this portion being located alesser distance from the aperture 55 than the portion 82. The portion 83does merge, as one continues to move notionally around the planetarygear carrier in an anti-clockwise direction with a portion which extendsback out to the full diameter of the planetary gear carrier as found asone re-encounters the inwardly directed step 80.

It is to be observed that in the condition illustrated in FIG. 6, withthe depending lug 31 of the catch 27 engaging the surface 70, the arm 37of the catch 36 is spaced from the outer periphery of the planetary gearcarrier 48, permitting the planetary gear carrier 48 to rotate freely.As will become clearer from the following description, the planetarygear carrier rotating any net is withdrawn from the roller retractor.Thus in this condition of the described embodiment the full length ofthe net 3 can be withdrawn from the roller retractor 2. It is to beappreciated, therefore, that the catch will have the conditionillustrated in FIG. 6 when the seat back is in the position 9 asillustrated in FIG. 2.

It is also to be observed, with reference to FIG. 6, that the latch 36is pivotally mounted for movement relative to the catch 27 and isspring-biassed, by spring 42 to a position in which the upper arm 37extends upwardly above the catch 27. The spring biassed arm enters theplanetary gear housing 41 (not shown in this figure) through the slot45, so that the free end of the arm 37 is located adjacent the peripheryof the planet carrier 48. The projection 41 provided on the lower arm 38of the latch engages the underpart of the forwardly projecting nose 30provided on the catch 27, to prevent the latch 37 rotating too far.

The arrangement will maintain this condition, as illustrated in FIG. 6,until the seat back has been moved up to the position 8 as illustratedin FIG. 2. As the seat back approaches the position 8, as illustrated inFIG. 2, the striker component 10 begins to enter the guide slot 14, andthe striker element 11 engages the upper part of the side wall of theslot 72, causing the locking member 25 to rotate in a clockwisedirection to such an extent that against the spring bias imparted to thecombination of the latch 27 and the manual release lever 34 by thespring 36, the latch 37 moves in a clockwise direction to bring thedepending lug 31 into an engagement with the recess 71. The componentsof the locking mechanism initially illustrated in FIG. 6 then have thecondition illustrated in FIG. 7. It can be seen that the U-shapedchannel 72 is now substantially vertically oriented, and consequentlyretains firmly within it the striker element 12. The depending lug 31 isreceived within the recess 70, thus preventing further rotationalmovement of the locking element 25.

It can be seen that the upper arm 37 of the latch 36 has been moved toan upper position, as compared with the position illustrated in FIG. 6.The free end of the arm is biassed against the arcuate surface 83forming part of the periphery of the planet gear holder 48. Should theplanet gear holder 48 attempt to rotate in the anti-clockwise direction,such rotation will be prevented by engagement of the step 81 with theend of the upper arm 37 of the catch 36. However, should the planetcarrier 48 rotate in a clockwise direction, as the planet carrierrotates, the outer periphery of the planet carrier will engage the uppersurface of the upper arm 37 of the latch 36, causing the latch 36 topivot about the pivot axis defined by the support stud 29, with thelower arm moving downwardly against the bias provided by the spring 42.

It is to be appreciated that as the planetary gear moves in theanti-clockwise direction, net 3 is being paid out from the retractorroller 2, whereas when the planet carrier 48 moves in a clockwisedirection, the net 3 is being wound on to the retractor roller 2. Thestep 81 is so positioned that the step 81 is brought into engagementwith the free end of the arm 37 of the latch 36 when a sufficient lengthof net has been paid out to reach from the top of the back 1 of the seatto the hook 7 in the roof when the seat is in the position 8 asillustrated in FIG. 2 of the accompanying drawings.

If the seat back is moved from the position illustrated at 8 in FIG. 2to the position illustrated at 6 in FIG. 2, the effect is that thestriker component 10 is moved further into the slot 20. However, thismovement can only be achieved if the manual release arm 34 is initiallymoved so as to disengage the downwardly directed lug 31 from the recess71. When the lug 31 has been released from the recess 71, the seat backmay, of course, be moved forwardly to occupy the position illustrated at9 in FIG. 2, in which case the spring 26 will return the locking element25 to the position in FIG. 6, or instead, the seat back may be moved tohave the position illustrated at 6 in FIG. 2, in which case the strikercomponent 10 will be moved further into the slot 14, causing the lockingelement 25 to rotate further in the clockwise direction as shown inFIGS. 6 to 8 against the bias provided by the spring 26. It can be seen,therefore, that as the locking member 25 continues to rotate, thestriker element 12 moves out of the channel 72, whilst the strikerelement 11 moves into and is received by the channel 75. If the manualrelease arm is then released, the depending lug 41 carried by the catch27 engages the abutment 73 with the lower end of the depending lugresting on the planar surface 74. The spring bias provided by the spring26 biases the abutment 73 of the locking member 25 into firm engagementwith the depending lug formed on the catch 27.

It is to be noted that when the catch is in this condition, the upperarm 37 of the catch 36 is spaced slightly further out from the centralaperture 55, than when the components were in the condition illustratedin FIG. 7. The free arm 37 of the catch 36 is now positioned to engagethe step 80 and the associated arcuate surface 82. Again, rotation ofthe planet carrier in the anti-clockwise position is prevented, whilstrotation in the clockwise direction is permitted.

FIG. 9 illustrates the catch and latch in position of FIG. 6, showingthe planet carrier 48 and the associated planetary gear wheels. It canbe seen quite clearly, in this condition, that the planet carrier 48 andthe associated planetary gear wheels 52,53,54 may rotate freely.

FIG. 10 illustrates an alternative position, corresponding to theposition of FIG. 6, and it can be seen that the latch 36 is in such aposition that the free end of the upper arm 37 is substantiallyco-aligned with the step 81 of the planet carrier 48. Should the planetcarrier 48 rotate, from the position illustrated, in the anti-clockwisedirection, which is the direction in which it will rotate should the netbe drawn out from the roller retractor 2, the net will be paid out untilstep 81 abuts the free end of the arm 37. No further net may then bepaid out.

FIG. 11 is a view corresponding to FIG. 10 illustrating a conditionequivalent to that shown in FIG. 8. Here, it is to be noted that thefurther length of net may be pulled out, as compared with the conditionshown in FIG. 10, while the planet carrier 48 rotates by a few moredegrees. However, in the condition of FIG. 11, the free end of the arm37 is rotated substantially in alignment with the step 80 of the planetcarrier, and when the planet carrier has rotated so that the step 80 isbrought into abutment with the free end of the arm 37, the planetcarrier will again be locked in position.

When the planet carrier is locked in position, the plant wheels 52,53,54are locked in position and consequently, the sun gear 56 will be lockedin position. As a consequence the spider 57 is locked in position.

FIG. 13 illustrates the spider 57, the rollers 58,59,60, the clampingelement 61 and clamping ring 62. The spider 57 may be moulded of aplastics material.

It is to be observed that the spider 57 comprises six arms. Three arms90,91,92 are equi-angularly spaced. Each arm is relatively wide and isthus rigid. Each arm terminates with two forwardly directed protrusions93,94.

Intermediate the arms 90,91,92 are three equi-angularly spaced arms95,96,97. Each of these arms terminates in a forwardly directedprotrusion 98. The arms 95,96,97 are made sufficiently thin to beresilient and flexible.

The clamping element 61 has a substantially hexagonal central aperture100 formed therein which is adapted to receive the hexagonal outersurface of the bearing 64 provided at the end of the roller 63 so thatthe clamping element 61 moves in synchronism with the roller 63.

The outer surface of the clamping element 61 defines threeequi-angularly spaced recesses of U-configuration, such as the recess101 each adapted to receive a projection such as the projection 98 onone of the resilient arms 95,96,97.

Equi-angularly spaced between the recesses 101 are inclined cam faces102. As can be seen in FIG. 13, each cam face 102 is associated with aroller 58, the roller 58 being located between the arms 93,94 of asubstantially rigid arm such as the arm 90. As can be seen in FIG. 13,the roller 58 is initially separated from the inner periphery 103 of theclamping ring 62.

In the event that the sun gear 56 is prevented from rotating, should theroller 63 still rotate in a sense in which the net 3 is being paid outfrom the roller, the small rollers 58,59,60 will be entrained by therelative movement of the member 61 (which co-rotates with the roller 63)and will move up the cam faces 102 (see FIG. 17) to become clampinglyengaged between the clamping member 61 and the inner face of theclamping ring 62. As this occurs the resilient arms 95,96,97 becomeslightly deformed. The rollers, as seen in FIG. 17, become wedged firmlybetween the cam faces 102 and the inner periphery of the clamping ring62, and thus prevent further rotation of the roller 63 of the retractorroller mechanism 2. The resilience in the arms 95,96,97 returns therollers 58,59,60 to their initial position (i.e. the FIG. 13 position)when tension applied to the net tending to withdraw the net from theroller 63 is released.

Referring now to FIG. 18 of the accompanying drawings, a modifiedembodiment of the invention is illustrated in which the planetary gears,the planetary gear carrier and the fixed ring gear are replaced by asingle moveable ring gear 104, which has a toothed interior 105 whichengages with the sun gear 56 mounted on the spider 57. It can be seenthat the axis of rotation of the spider is no longer concentric with theaxis of the ring gear.

The exterior periphery of the ring gear defines a discontinuity or step106 which corresponds to the step 80 or the step 81 described above. Theupper arm 37 of the latch 36 is of a more upwardly directedconfiguration than in the previously described embodiment, but it can beseen that with the catch 27 in the position illustrated, the upper arm37 of the latch 36 is located to engage the step 106 to prevent rotationof the ring gear 104 in the anti-clockwise direction. This will, ofcourse, stop rotation of the sun gear 56 with the consequences describedabove with regard to the earlier embodiments.

It is to be appreciated that in the embodiment of FIG. 18 only one step106 is provided, corresponding to a specific length of net beingwithdrawn from the retractor roller 2. However, in this embodiment, twosteps could be provided, as in the embodiment described above,corresponding to two slightly different lengths of net. Of course, theembodiment of FIG. 1 might be modified to have only a single step as inthe embodiment of the FIG. 16.

It is to be appreciated, therefore, that in use of the embodiments ofthe invention, the amount of net that can be withdrawn from theretractor roller depends upon the position of the back of the seat, andthe length of net is sufficient to reach the associated hook or hooksprovided in the ceiling so that he net is stretched relatively a tightlybetween the back of the seat and the hooks provided in the ceiling ofthe motor vehicle to prevent luggage from travelling forwardly.

What is claimed is:
 1. A safety device and seat combination for use witha motor vehicle having a roof, comprising: a seat including a seat backhaving a top portion, wherein the seat and seat back are moveable amongvarious positions; a roller retractor mounted adjacent the top portionof the seat back and including a roller; a protective element having alength wound upon the roller of the roller retractor and a lengthextracted from the roller retractor, wherein the extracted length of theprotective element has one end adapted to be anchored to the roof of thevehicle, and wherein the extracted length and the wound length arevariable in dependence on the various positions of the seat back; atleast one means for anchoring the end of extracted length of theprotective element to the roof of the vehicle; and a locking mechanismfor engaging the roller retractor so that no more than a predeterminedlength of the protective element can be extracted from the rollerretractor, wherein the predetermined length is of a sufficient length toenable the end of the extracted length of the protective element to besecured to the means for anchoring.
 2. A safety device and seatcombination according to claim 1, wherein the anchoring means is adaptedto be mounted on the roof of the vehicle.
 3. A safety device and seatcombination according to claim 1, wherein the roller retractor comprisesa retractor roller and the protective element is reversibly wound on theretractor roller.
 4. A safety device and seat combination according toclaim 1, wherein the locking mechanism is constructed and arranged sothat the retractor roller is prevented from rotating when the lockingmechanism is engaged.
 5. A safety device and seat combination accordingto claim 1, further comprising a release mechanism for releasing thelocking mechanism from engagement with the roller.
 6. A safety deviceand seat combination according to claim 1, wherein the retractor rollerincludes an element that rotates with the roller, and wherein thelocking mechanism comprises roller engagement means for engaging theroller element to prevent rotation of the roller, means for actuatingthe roller engagement means, said actuating means having a gearmechanism, and selectively positionable means for engaging the gearmechanism such that the extracted length is dependent upon a position ofthe top portion of the seat back relative to the anchoring means.
 7. Asafety device and seat combination according to claim 6, wherein thegear mechanism comprises a planetary gear mechanism having planetarygears and a sun gear.
 8. A safety device and seat combination accordingto claim 7, wherein the planetary gear mechanism further comprises aring gear fixedly mounted in a position relative to the seat back, aplanetary gear carrier rotatably mounted in a position for carrying theplanetary gears, wherein the sun gear engages the planetary gears and isconnected to the roller engagement means, and a latch being movable toselected positions depending upon the position of the seat back andadapted to engage the planetary gear carrier.
 9. A safety device andseat combination according to claim 8, wherein the planetary gearcarrier has an outer periphery and wherein the engagement meanscomprises at least one step provided in the outer periphery of theplanetary gear carrier.
 10. A safety device and seat combinationaccording to claim 9, further comprising a striker component and lockingmember, wherein the striker component is constructed and arranged tostrike the locking member such that the locking member moves when theseat back is moved to at least one of the various positions such thatthe position of the latch is changed.
 11. A safety device and seatcombination according to claim 10, further comprising a catch adapted toengage the locking member and carry the latch.
 12. A safety device andseat combination according to claim 11, further comprising releasingmeans for actuating the latch, catch, and planetary gear mechanism suchthat the roller retractor rotates freely until the locking mechanismre-engages.
 13. A safety device and seat combination according to claim6, further comprising at least one ring and sun gear mechanism connectedto the roller engagement means, wherein the ring and sun gear mechanismhas at least one ring gear with an outer periphery and at least one sungear, and wherein the at least one ring gear is movably mounted suchthat it is in direct contact with and is driven rotationally by the atleast one sun gear.
 14. A safety device and seat combination accordingto claim 13, wherein the ring gear has an outer periphery and whereinthe roller engagement means comprises at least one step provided in theouter periphery of the ring gear.
 15. A safety device and seatcombination according to claim 6, wherein the roller engagement meansfurther comprises a clamping member having a periphery defining at leastone cam surface and a movable clamping element located between the camsurface and a clamping surface that surrounds the clamping member,wherein the clamping member is constructed and arranged to rotate withthe roller, and wherein the locking mechanism is constructed andarranged to retain said movable clamping element substantially in aposition.
 16. A safety device and seat combination according to claim 1,further comprising a latch movable to selected positions in dependenceupon the position of the seat back and adapted to engage the rollerengaging means.
 17. A safety device and seat combination according toclaim 1, wherein the protective element comprises one or more from thegroup consisting of netting, fabric, screening and sun-screening.
 18. Asafety device and seat combination according to claim 1, wherein theroller retractor has two ends, and wherein the locking mechanismincludes a first locking mechanism at one end of the roller retractorand a second locking mechanism provided at the other end of the rollerretractor.
 19. A safety device and seat combination according to claim1, wherein the anchoring means is constructed and arranged to provide anumber of different anchoring positions.
 20. A safety device and seatcombination according to claim 1, wherein the roller retractor isrotationally biased toward retracting the protective element.